Nineteen patients had serum FGF21 levels above the upper limit (116.591 pg/ml), including 10 patients with epilepsy (7/15, 46.7%), 5 patients with myasthenia gravis (5/6, 83.3%), 3 patients with DMD (3/7, 42.9%), and 1 patient with viral encephalitis (1/2, 50%). Here, DMD is linked to myasthenia gravis.